Objective <p>This cross-sectional study investigated the association between social support and stress among Turkish citizens and immigrant pregnant women from Syria, Iraq, and Afghanistan.</p> Methods <p>The study was conducted with 600 pregnant women at a tertiary training and research hospital in Istanbul, categorized into three cohorts: Turkish citizens (<i>n</i> = 200), short-term immigrants (<i>n</i> = 200), and long-term immigrants (<i>n</i> = 200). Participants were evaluated for perceived social support and prenatal stress levels using validated scales.</p> Results <p>Although sociodemographic characteristics were largely comparable across groups, short-term immigrants exhibited significantly lower educational attainment, higher unemployment rates, and greater income–expenditure imbalance. Turkish participants reported significantly higher levels of perceived social support, particularly from familial networks. Conversely, both immigrant cohorts demonstrated elevated pregnancy stress scores relative to the Turkish group. A statistically significant negative association between social support and pregnancy stress was identified across all cohorts. Notably, long-term immigrant women appeared to derive the most substantial benefits from social support in mitigating prenatal stress.</p> Conclusions <p>Perceived social support was highest among Turkish pregnant women, followed by long-term and short-term immigrants, respectively. Pregnancy-related stress was significantly more pronounced in both immigrant groups compared to the native population. These findings underscore the critical role of social support systems in alleviating prenatal distress among vulnerable immigrant populations.</p>